1. Field of the Invention
The present invention relates to the remote measurement of properties of transparent media, such as subsurface ocean temperature profiles, and in particular to improved apparatus for and a method of remotely measuring such temperature profiles from surface or subsurface vessels or aircraft.
2. Description of the Prior Art
There are several applications for remotely sensing or measuring the temperature of a bulk transparent medium such as water. One such application is the sounding of temperature profiles in the ocean which is useful for a variety of oceanographic purposes such as in measuring the depth of the thermocline, sensing internal waves, measuring heat content of the oceans for meteorological applications and mapping acoustical propagation paths sensitive to temperature gradients. Intrasensitive temperature sensors, such as thermistors, thermocouples, etc., have been used in the past for these purposes but, because they are not remote sensors, they are slow and awkward. A remote sensing technique in wide use is the monitoring of thermal radiation; this technique, however, is limited to measuring predominantly surface temperatures.
This invention is directed to an improved technique for remotely measuring temperatures within, i.e., below the surface of suitable transparent media or substances, for example sea water.